Switching mechanism for telephone-circuits.



No. 877,033. PATENTBD JAN. 2 1, 1908.

A. K. mmmammmmo. smmITGHINGI MECHANISM PoR TELEPHONE CIRCUITS.

APPLIGATIQN FILED MAR.15, 1905.

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ALBERT KOCH ANDRIANO, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TODIRECT-LINE GENERAL TELEPHONE COMPANY, OF SAN FRANCISCO, CALIFORNIA, ACORPORATION.

SWITCHING MECHANISM FOR TELEPHONE-CIRCUITS.

Specification of Letters Patent.

Patented Jan. 21, 1908.

Application filed March 15,1905. Serial N0. 250,155.

To all whom 'it may concern:

Be it known that I, ALBERT KOCH AN- DRIANO, a citizen of the UnitedStates, residing in the city and county of San Francisco and State ofCalifornia, have invented new and useful Improvements in SwitchingMechanism for T elephone-Circuits, of which the following is aspecification.

This invention relates to improvements made in portableswitching-mechanism for telephone-circuits, applicable more particularlyto what are known as desk-telephones, and designed especially forsetting up and controlling circuits for ringing, or calling, and fortalking between one station and another in those systems wherein theconnecting and calling are performed directly from the station.

The improvements comprise certain novel construction and combination ofswitching or line-selecting mechanism, in which a single movableswitch-piece capable oi being moved in either direction over thelinecontacts contains two sets or series of circuitclosing contacts, oneof which operates to select the line for the talking-circuit, while theother set or series controls through electrically actuated means thecompletion of the talking circuit in such manner that the switch can notbe disturbed after it is once placed to the desired line g that is tosay, no further or additional adjustment of the movable contact-piececan be made in either direction without breaking the circuit and placingthe station back on its own line. A circuit-breaking means mechanicallycontrolled from or through the telephone-hook is also combined with thisline-selecting switch, through the medium of which the primary-circuitof the station, or the local circuit that includes the induction-coil,the transmitting instruments and a source of current, is automaticallyreturned to its own line independently of the switching-mechanism, orthe position occupied by its movable switch-piece, by the operation ofreturning the receiving instrument to place on its hook.

The nature of my said improvements, and the manner in which the same areapplied to and embodied in a portable switch-stand and telephone-supportof the kind referred to, are explained at length in the followingdescription, in which the accompanying drawings are referred to byiigures and letters Figure l is an elevation of the instrument havingall the parts of the switching-mechanism contained in the base; aportion of the external walls or shell of the pbase and the pillarbroken away to expose parts within. Fig. 2 is a top-view of thevstationary linecontacts and the movable-contacts of the line-selectingswitch. Fig. 3 is an inverted or reversed plan of the contact-platesthat overlie the line-contacts and the movable circuit-closer shown inFig. 2. Fig. 4 is a transverse section taken in a vertical plane throughthe two series of stationary-contacts and the intermediate plates; thetwo insulation-blocks carrying the upper and lower series beingseparated from each other. Fig. 5 is a top-view, on an enlarged scale,of the switching-mechanism, and the circuitclosing devices that arecontrolled from the telephone-hook. The dial and the stationarycontact-plates immediately beneath it are broken away in part, Fig. 6 isan elevation, in detail, of the stationary and movable members of thecircuit-closer that is controlled from the telephone-hook; the elevationbeing taken from the left side Vof Fig. 5. Fig. 7 is a side-elevation,in detail, of the iiXed stops and the movable-stops of the ringing-key.

In the following description the term stationary contacts is used todesignate the points 2 in the switch which are the terminals ofindividual lines entering or running out from the station. The termmovable switch-piece, means the centrally-pivoted member of the switchthat rides over and makes contact with the points 2. The word home-line,means the line or conductor individual to the station; and the termprimary-circuit, designates the local circuit of every station thatincludes the transmitting device and the inductive apparatus, and isconnected with a source of current through the home-line peculiar to thestation.

These improvements in switching and circuit-controlling means, as I haveillustrated them and will now proceed to describe them, are arranged foroperation in connection with stations in which the primary-circuit ofeach is normally connected into its home-line through thecircuit-controlling means and not through the line-switch; so that themovable contact-piece or member of the lastn'amed switch performs nopart in connecting the primary-circuit with or into its own homeline andsource of current. A telephone system having circuit connections such asjust described is shown and claimed in my Patent No. 846,889, datedMarch 12,1907.

The Jfunction of the line-switch is to select the home-line of thestation to be communicated with, and to place that line in properrelation to form in connection with the line provided Jfor the otherside a complete metallic circuit between the two stations. No returnmovement or adjustment of the switch to the home-line of the station isrequired; and its movable-member may beleft at any point or positionwithout affecting the operation of the instrument. The operation ofconnecting the primary-circuit with its own line again after every timeof use, as well as of making connection with the home-line of anotherstation, is performed by that part of the lapparatus designated as thecircuit controlling means. The switchingmechanism is well adapted alsofor use in those systems where the battery or source of current islocated inside and not outside the switch.

The construction and arrangement oi' the switching-mechanism will bedescribed with reference to Figs. 2, 3, 4 and 5. The stationary-contacts2 that form the terminals of the line-wires at the switch in everystation aie embedded in a block g of insulating fiber 'fixed on thebed-plate e, the line-wires being con- 'nected individually to thecontacts in the well-known manner. The spindle d carrying the movableswitch-piece 5 is rotatable in bearings 22 in the block g, and also inanother and similar block g1 situated above the block g. To theunderside of the upper block g1 are iiXed contactlates 7 8; room betweenthe two blocks being afforded for the movable switch-piece. The twoblocks g g1 are secured to the bed-plate by screws 25, and by spacingwashers 26 that support the upper block and maintain it at properdistance from the lower block. The contacts 4 6 on the movableswitch-piece 5, insulated from each other, are iiXed on the ends of thetwo oppositelyextending arms of the piece 5, so that the springs 4 willtouch the contacts 2, one at a time, as the switch-piece is turned, andwill also ride continually on the central contactring 3 lying within thecircle of stationarycontacts. The contact ring 3 is insulated from thelast-named contacts, and is so connected by a conductor or connectioninto one side of the primary-circuitthat the ring 3 forms thecircuit-closing means between the rimary-circuit and any selected one ofthe ines that has a terminal in the circle of contacts 2, lwhen thecontact-spring 4 is placed on the proper contact. In like manner thecontact-spring 6 at the opposite end of the switch-piece will bridge thespace that separates the inner plate 7 from the outer plate 8 on theupper block g1, and thus complete me'- tallic connection between them.

The contact-piece 6 is so placed with reference to the othercontact 4that, while the latter is resting on a line-contact 2, the contact 6will touch the contact-plates 7 8 above it only on the outer side, as on81, and will not bridge the gap .or space 9 that separates the two parts7 8, and the circuit in which the arts 7 8 are situated will then beopen. ut, on the other hand, the contact-spring 6, when brought intosuch position that it will bridge the space 9 and close 'the circuit bytouching one of the inner parts 71 and an adjacent outer part 81 willclose the circuit; and thus on the instant that the switch-piece 5 ismoved in either direction a sufficient distance to carry thecontact-spring 4 away from the line-contact it will also connect the twoplates 7 8 across the gap 9, and complete the circuit through thoseparts. This results from the peculiar construction of the contact-plate7 8 and the arrangement of the same with respect to the other members ofthe mechanism. The operation will be more clearly understood byreferring to Figs. 2, 3 and 4. The contacts that close and open thecircuit through the circuit-controlling means before mentioned are seenin Figs. 3 and 4, where the two insulation blocks g g1 and thecontact-plates 7 8 are shown in their relative positions. The workingposition of the upper portion, represented in Fig. 3, is directly overthe parts seen in Fig. 2; and the face of the block g1 which isuppermost in Fig. 3 will overlie and face the circle of contacts 2 inthe switch, and will lie next to the contact-spring 6 on theswitch-piece when placed in position.

The inner portion 7 and the surrounding portion 8 of the contact-plateon the block g1 are separated from each other by a continuous slit orgap concentric with the axis of the movable-piece 5 and having alternatesalient and rentering angles of such proportions that the angularmembers or sections 81 of the outer member present a sufficient breadthof surface for the contact-spring to rest on without touching thesimilar angular section or point 71 lying on either side of a section81; the position assuinedby the contact-spring 6 while thecontact-spring 4 is resting on a line-contact will put it in contactwith a section 81 alone. Movement of the switch-piece in eitherdirectionV out of working position on a line-contact will cause thecontact 6 to touch the nearest section 71 These secconvenience insetting the switch-piece to the desired line the spindle is providedwith a dial-plate 31 located and operating in the well-known manner toindicate to the user the position of the switch with respect tothecontacts 2 that are concealed from view. The construction and operationof the circuit-closing and openin means will be underst'ood from thedetalls Figs. 5 and 6 in' connection with the other figures of thedrawings. lt should be noticed in the present construction that thecircuit-closing and opening means does not control theswitching-mechanism, as the latter has no resetting movement and doesnot require to be returned to an initial position after each' time ofuse.

The complete instrument is provided with a ringing-key m2, and a hingedsupport j) for the transmitter, in addition to the supporting hook h1for the receiver, in the usual manner.'

As the switch-piece 5 has no spring to return it to position and isfreely movable in either direction in making a switch, the complicatedlocking and releasing mechanism heretofore required to reset the switchto normal position by the act of hanging up the receiver is renderedunnecessary. Such controllingdevices being omitted from the presentconstruction, the mechanism is greatly simplilied both in number ofparts and in its operation. lts durability as well as its reliability ofoperation under all the conditions of use to which theseswitching-devices are exposed are materially increased. In addition toits function of selecting any one of the lines of the other stations,this switchingmechanism also controls the connection between itsprimary-circuit and its own homeline, as well as with the home-line ofthe selected station, through the circuit-controlling means which islocated between the switch and the primary-circuit in such manner thatwhile the station is not being used its primary-circuit will beconnected to its own home-line; or, when the line switch is moved tomake a switch and the operation of ringing up the other station isperformed, the primary-circuit will be connected to the home-line of theselected station to which the switch has been set.

It will be understood that the contact plates 7 and 8 constituterespectively the terminals of a circuit that includes an electro-magnetand some suitable source of power, such as the battery employed forringing the call bells of the telephones; and that the saidelectro-magnet is arranged to operate a cut-out or circuit controllerthat serves to disconnect the primary-circuit from the line of theselected station, and to return it to the home-line of the station wherethe call was made. From this it is evident that the line-switch cannotbe disturbed from its position after being set to a selected line,

without electrically connecting the terminal plates 7 and 8 and causingan automatic restoring of the parts of the instrument to normalposition, that is with the primary-circuit connected with its home-lineonly, and disconnected from the line of every other station. It is notpossible, therefore, for al user to place his instrument temporarily incircuit with the home-line, by switching and closing his ringing-key tooperate the circuit-closer, and then attempt to get the home-line ofanother station, by moving his line-switch out of position, withoutgoing through the same operation of switching and calling, by whichoperation his own instrument will be disconnected from his line-switchand restored to its initial position.

l do not herein 'claim the system of automatically controlling the localtalking circuit whereby secrecy of service between stations is insured,such as above described, as l have made such system the subject-matterof another application for patent which l have filed of even dateherewith, Serial Number 250,154.

The switch-piece 5 is caused to perform and bring about the twovoperations of selecting the line and controlling the connection of theprimary-circuit by making the switchpiece 5 and the movable member 6 asingle part.

The circuit-closer. that is operated mechanically from thetelephone-hook consists of a tilting-lever. 10 supported on pivots l2and provided with two circuit-closing contact-strips 35-36, bothinsulated from the lever and so arranged between two sets ofcontact-springs 15-16, 17-18 that when one end of the lever is depressedin one direction it will close the circuit through the conductors ofwhich the contact-springs 15-16 are the terminals, and at 'the'same timeopen the springs 17-18 of the set at the opposite end. Or, if depressedat the other end, the lever will close the springs 17-18 and open theother set 15-16. An additional circuitclosing piece 20 carried by thelever 10 acts to connect a third contact-spring 19 at the time that theouter end of the lever is depressed to connect the springs l7-18. Thecontacts 15-16 operate to cut out the bell when the talking-circuit iscompleted by removing the receiver from the hook; and the contacts 19-20make or break the primarycircuit to the line by the act of taking downor hanging up the receiver. The contacts 17-18 open and close theringing-circuit.

.A rod 13 loosely attached to the arm 7L of the hook on one side of itsfulcrum-point 33 extends down through the pillar to the lever 10, onwhich its lower end rests with suiiicient pressure under the weight oflthe receiver on the hook to depress the inner end of the lever 10 andhold up its outer end clear 0I the contact-springs 17-18- On beingrelieved of the weight of the receiver the lever 10 will be tilted inthe opposite direction through the tension of a spring 21 attached tothe end of the lever 10 and to a 'fixed point on the plate e of theframe. These parts are mounted on the plate e of the frame, and areinsulated from one another and from other metallic parts, wherenecessary, by blocks of linsulation berf-ga common aXis, the contacts inthe lower series comprising insulated contact-points, and a contact-ringconcentric therewith, the contacts in the upper series comprising aninner plate having alternate and concentric salient and rentering anglesand an outer ring having salient and rentering angles corresponding inOrder and position to those on the inner-plate, situated in the sameplane and insulated therefrom; in combination with a rotatableswitch-piece centrally pivoted between the said lower series and upperseries of contacts and movable in either direction around the circle,two separate contact-pieces carried thereby and insulated from eachother, one of said contact-pieces operating to connect with thecontinuous contact-ring the selected stationary-contact to which it maybe set, and the other contact-piece adapted by its position to rest onone side of the space between the inner plate and the outer ring of theupper contacts when a contact in the lower series is in metallicconnection with the contact-ring, or to bridge the said space betweenthe upper contacts when the switchpiece is moved.

2. In a telephone switching-mechanism, the combination of two circularseries of staf tionary-contacts in parallel planes one over the other,the contacts composing one series constituting separate terminals forindividual lines, and a continuous contact-ring common to said contacts,insulated therefrom, the contacts in the other series comprising aninner plate having concentric and alternate salient and renteringportions, and a surrounding ring having corresponding but relativelylarger salient and rentering portions on the inner edge parallel `withthe corresponding portions on the inner ring, and separated therefrom; arotatable switchpiece pivotally mounted between said upper series andlower series of contacts, and adapted to move in either direction, andcontact-pieces on said movable switch-piece Jfor making and breakingconnection between the contacts in one series in-alternate order tovthose in the other series by the same movement of the switch-piece.

In testimony whereof I have hereunto set my name to this specificationin the presence of two subscribing witnesses.

ALBERT Koen AN-DRrANo.

Witnesses:

B. W. MORGAN, A. V. B. Davis.

